Mobile phones have become a popular communication equipment in our daily life. The main body of the phone becomes smaller and smaller in size to facilitate carrying around by a user; however, the antenna of a mobile phone has, so for, no any improvement, such as the length of the antenna is unable to vary and having a poor reception function, which are deemed drawbacks thereof. Even an extension antenna is still deemed too long to meet the requirement after being retracted into a short one. If a connector of an antenna is added thereto, the whole length of an antenna is still too long to carry or for storage. The antenna might be bent at an angle of 90 degrees for shortening its length; unfortunately, the reception function would be affected as a result of no perfect high-frequency connector being available, and therefore no such antenna is used. Generally, a flexible rod antenna is used on a mobile phone, but the length of such an antenna is still deemed too long. Since the phone signal is a high frequency signal, the impedance-matching member has to be adjusted and tested carefully before being installed in place; such adjusting and testing procedures have become a bottle-neck in the assembling line, aside from the lack of quality assurance of the impedance-matching circuit and the reception poor result.